Fibromyalgia (FM) is a chronic, multisystem disorder affecting approximately 2-4% of the general population, predominantly women. It is characterized by widespread musculoskeletal pain, fatigue, sleep disturbances, anxiety, cognitive impairment, and autonomic symptoms such as gastrointestinal irregularities, Raynaud-like phenomena, and sicca complaints. The pathophysiology remains incompletely understood but is thought to involve central pain sensitization and dysautonomia.
Emerging evidence indicates that FM is associated with increased cardiovascular risk. Observational studies have demonstrated a higher prevalence of endothelial dysfunction, arterial stiffness, arrhythmias, and coronary artery disease in FM patients. Mechanistically, chronic sympathetic overactivity and persistent catecholamine release may increase myocardial oxygen demand, impair microvascular perfusion, and lead to subtle myocardial dysfunction. Autonomic imbalance has also been documented by heart rate variability studies, supporting impaired sympathetic-parasympathetic regulation. Importantly, the overlap between FM symptoms (fatigue, poor sleep, reduced functional capacity) and those of heart failure suggests a potential underrecognized cardiac component in FM.
Conventional echocardiography relies on left ventricular ejection fraction (LVEF) to evaluate systolic function. However, LVEF may remain normal despite underlying myocardial impairment and is strongly affected by loading conditions and observer variability. Many patients with heart failure present with preserved ejection fraction (HFpEF), underscoring the limitations of LVEF as an early marker of myocardial dysfunction.
Global Longitudinal Strain (GLS), assessed using two-dimensional speckle-tracking echocardiography (2D-STE), has emerged as a more sensitive and reproducible tool for detecting early myocardial dysfunction. GLS abnormalities can precede measurable reductions in LVEF and have prognostic value across diverse conditions including ischemic heart disease, hypertension, valvular disease, chemotherapy-related cardiotoxicity, and heart failure.
Preliminary studies in FM populations suggest possible subclinical myocardial involvement. Some reports describe increased risk of diastolic dysfunction and impaired GLS in FM patients, possibly reflecting the impact of chronic stress and autonomic dysregulation on cardiac mechanics. Nevertheless, systematic and adequately powered investigations remain scarce.
This prospective, observational, case-control study is designed to fill this knowledge gap. The study will enroll 59 FM patients diagnosed according to the 2010 American College of Rheumatology (ACR) criteria and 59 age- and sex-matched controls without systemic rheumatic disease. Echocardiographic examinations will be performed using a standardized protocol (Vivid E95, GE Healthcare), and GLS will be measured offline with EchoPAC software, following the American Society of Echocardiography guidelines. Disease severity in FM will be assessed using the Fibromyalgia Impact Questionnaire (FIQ).
The primary hypothesis is that FM patients will demonstrate a higher prevalence of impaired GLS, consistent with subclinical ventricular dysfunction, compared with controls. The secondary hypothesis is that higher FIQ scores will correlate with greater impairment in GLS, suggesting a relationship between disease burden and cardiac involvement.
The anticipated significance of this research lies in clarifying the cardiovascular component of fibromyalgia. Early identification of myocardial dysfunction using GLS may allow for improved risk stratification, closer clinical monitoring, and preventive strategies aimed at reducing long-term cardiovascular morbidity. Beyond its clinical relevance, this study also extends the application of GLS into a non-traditional, rheumatology-related context, reinforcing the systemic nature of FM and the need for interdisciplinary management approaches.
